1. Field of the Invention
The invention relates to the field of pipe cleaning or pipe cleaning tools and in particular to pipe cleaning tools or pigs which use roller cutters.
2. Description of the Prior Art
Reinhart, et al., "Pipe Cleaning Equipment," U.S. Pat. No. 4,538,316 (1985) shows a swivel propulsor unit applied to swiveled pairs of cutting heads having spring-loaded cutter arms. Reinhart '316 shows at least one cleaning unit with pivotal arms and one propelling unit in swiveled connection with each other. The pig has cleaning heads 1a and 1b and propulsion unit 2 connected by hinged knuckles 23 allowing tilting of up to 3 degrees to facilitate passage of the equipment through pipe bends. Each cleaning unit has a head 7 with four pivoted cutting arms 3 and four projecting ribs 10 for breaking and disintegrating pipe deposits. The arms have a variable profile from a triangular shape near the pivot and axis to dual contact areas near the rear end of the arms. The variable profile provides a means for splitting the deposits at the leading edge and scraping the deposits at the rearward edge. The arms have up to four rollers 30, best depicted in FIG. 2, to facilitate passage of the cutters through pipe valves and other bends without effecting the cleaning efficiency of the device.
Reinhart's '316 rollers 30 in the depiction of FIG. 2 are placed on a section of cutter arm 3 that normally is not used for cutting or breaking the pipe deposits. Rollers 30 themselves do not appear to be used in any cutting function. See column 6, lines 36-46. Reinhart '316 uses the rollers for facilitating movement through valving and pipe bends on a pivoted arm. Reinhart '316 fails to show a cutting function combined with the rolling element.
Reinhart, "Pipe Cleaner," U.S. Pat. No. 4,920,600 shows a pipe cleaner with flexible propulsor disks identical to Reinhart '316 but rigidly connected via a shaft to a plurality of entirely rigid cutters on a fixed cutter head. Reinhart '600's propulsor disks are made from leather which rapidly degrade in the hot caustic environment of a geothermal pipe and the tool has no means for bending or flexing to accomodate bends or internal restrictions within the pipe.
Brenholdt, "Pipe Line Cleaner and Locator," U.S. Pat. No. 2,601,248 (1952) shows a locator having a rotating magnet which rotates at approximately 5 Hertz combined with a pipe line scraper. The magnet is deployed in the scraper so as to avoid any type of interference with the cutting operation. An electric motor is used to turn the magnet and is powered by a battery. Magnet 16 is mounted on shaft 14 turned by motor 12 powered by battery 10. The substitution of an electromagnet for the permanent magnet is contemplated through the use of an interrupter circuit. See column 4, lines 5-39.
Brenholdt contemplates a separate power source for rotating the magnet as opposed to utilizing the fluid flow within the pipe. Clearly, Brenholdt's embodiment would likely be inoperable in a hot, corrosive and hostile environment unless very well sealed and insulated.
Saxon et al, "Tube Cleaning Tool for Removal of Hard Deposits," U.S. Pat. No. 5,153,963 (1992) shows a pig having a plurality of spaced freewheeling cutter wheels. Tool 1 with cylindrical body 3 has a truncated nose 27 with a nose portion 5. The main cylinder member 13 has cutting wheels 11 supported so that only a small portion of the wheel extends outwardly from the body envelope. The body is sized to be less than the tube diameter 67 to be cleaned and wheels 11 extend between the hard deposits and wall 71 of the pipe. Saxon has the roller cutters rigidly mounted in the cutting head.
Nutt, "Method and Apparatus for Cutting Taps in Sewer Lines," U.S. Pat. No. 4,887,585 (1989) describes a tool using a hydraulic-driven self-propelled cutter that cuts close to the side wall of a pipe without jamming. Tap cutter 10 has a frame 18 with hydraulic motor 14 having shaft 15 supporting and turning a bit 16. Frame 18 has four skids 20A and B, 22A and B, with rollers to allow passage of the assembly through the pipe, to allow passage over offsets in the pipe, to prevent rotation when used in the pipe. The use of the roller is provided at the end of the skids is described principally for improving the ability of the pipe to travel over offsets and intruding seams in the pipe. See column 4, lines 46-61. The rollers are not used for any cutting function, but only for stabilization of the frame during the tapping operation by bit 16. See column 5, lines 18-22.
Bilton et al., "Appliance for Scraping Interiors of Water Mains or Pipes," U.S. Pat. No. 576,425 (1897) describes a pig for cleaning rust, silt or deposits in a pipe which is designed to enable it to pass any permanent obstruction in the pipe and to go around ordinary bends. A spindle is fitter with two cones B and C, having radial grooves b and c holding pivotal cutters D and E. Resilient rings and washers are provided for adjusting the degree of pressure that the cutters will have against the interior of the pipe. The rear spindle is fitted with a ring N to which, if preferred, a bar magnet may be attached used in combination with a compass in order to locate the scraper.
Bilton shows rotatable cutting arms D and E used in combination with a magnet for purposes of location tracking. However, Bilton's cutters are not roller cutters and the magnet is not rotating.
Brackeen, "Cleaning Device for Pipe Lines," U.S. Pat. No. 2,332,984 (1943), shows a fluid pressure propelled pipe cleaning device which employs nozzle action to effect a first level of cleaning. As shown in FIGS. 1-6, the device which is inserted lengthwise into the pipe includes a head 12a, a series of flexible sealing disks 12b and 13, and brake shoes 21 and 22 for maintaining frictional contact with the inner surface of pipe 10. You will note parenthetically that FIG. 2 shows a rigid connection of a shaft from propulsor disks 13 into a cutting head 12a. Numerous water jets 14, 15 and 16 are defined in head 12a. The disk and brakes form a seal. Fluid is captured behind the device which generates the necessary pressure to propel it through the pipe. Some of the high pressure fluid is nozzled through jets 14, 15 and 16 so that the water stream exiting from these jet erode and dissolve the softer portions of material built up within pipe 10 immediately in front of the pig. Material not removed by the fluid jet action is subsequently scraped away by means of disks and brakes 12b, 13, 21 and 22.
Griffin, "Tube Cleaning Tool," U.S. Pat. No. 1,280,443 (1918), shows a tube cleaning tool used for tubes of condensers and the like. As shown in FIGS. 1 and 2, the tool has a front section with a helical scraper blade 1 and has a rear section piston 3 having a boss 7 defined thereon. In operation, the tool is inserted into the pipe to be cleaned and then propelled through it by high pressure water flow. Since the diameter of piston 3 is less than the interior diameter of pipe b, nozzling effect would inherently result as part of the propelling water is deflected by boss 7 through the space between piston 3 and the inner surface of pipe b out to the front section.
Hodgman, "Pipe Cleaning Machine," U.S. Pat. No. 1,181,310 (1916), shows a fluid propelled pipe threader. The device is intended to be used for Car the end of heavy rope or cable through pipe. However, the device employs a fluid effecting disk similar to your own concept. As shown in FIGS. 1-5, the device comprises an elongated buoyant body 1 having formed thereon a series of flexible disks 10 which are concentrically spaced apart. The diameter of disk 10, which project radially outward from the axis from the elongated body 1, are less than the inner diameter of pipe A through which the device is propelled. Consequently, pressurized fluid hitting the rear surface of the rearmost disk 10 imparts a driving force. The defective fluid passing through the space between the peripheral edge of each disk 10 and inner surface of pipe A jets forward to impart a driving force against the surface of the next disk 10. It is apparent that the force producing agitation of fluid created by the resulting nozzling effect in the case of the front most disk 10 will result in some erosion or dissolution of material lining the inner surface a.sup.1 of the section of pipe A immediately ahead of the device.
Littlefield, "Flow Propelled Sewer or Pipe Threader," U.S. Pat. No. 2,980,399 (1961), shows a device in FIG. 1 comprised of pistons 8, cleaning blades 12, rollers 18 and 20 and deflectors 11. As pressurized fluid imparts propelling force on pistons 8, some of the fluid passes through openings formed through pistons 8, passes by cutting blades 12 and is deflected around deflector 11. The fluid so deflected is jetted outward against the inner surface of the pipe at a point where the cleaning members engage the encrusted matter to be removed. The fluid disturbance dissolves and carries away the scraped residue.
Kruka, "Pipeline Pig with Restricted Fluid Bypass," U.S. Pat. No. 4,498,932 (1985), shows a pig which employs fluid nozzling to aid in pipe buildup removal. As shown in FIGS. 1-3, the pig comprises a foam body, a fluid passageway 1 and orifice 8. When inserted into a pipe and projected through the pipe by fluid flow, the outer surface of the pig's body, which conforms to the inner diameter of the pipe to be cleaned, functions to scrape away the built up material. Passageway 1 allows fluid from the back of the pig to flow to the front where it is nozzled by a set of outwardly directed jets 9 shown in FIG. 3. The resulting streams of fluid serve to agitate and suspend at least the soft portion of the build up just prior to scraping.